Math for photographers, or... how much space to leave empty around your subject?

<p>I am shooting a red carpet event this weekend. Don't get too excited, it's for my niece's 7th birthday party. :-)<br>

My sister-in-law has asked if I would be so kind as to take pictures of the girls as they are entering the party on the red carpet. Being the nice brother-in-law that I am (and because I'm the only one in the family with a decent camera), I gladly accepted.<br>

Here's the plan...</p>

<ol>

<li>Take pictures of the girls as they enter the party</li>

<li>Run to CVS to get the images printed as soon as possible</li>

<li>While at CVS the girls are decorating picture frames</li>

<li>Run back to party as quickly as possible to deliver the prints</li>

<li>Sister-in-law inserts prints into picture frames</li>

<li>Girls take frames home with them</li>

</ol>

<p>Here's the catch. The picture frames hold a 4x6 photo that is inserted in the back BUT, the front of the frame has an overlay that only allows the middle of the image to show through. The opening is 2x3, so my SIL says.<br>

Is there some sort of math I can use to figure our how much empty space to leave around each subject so they appear in the 2x3 area of the frame? Or is it just shoot and pray?<br>

The camera is a crop sensor Canon Rebel. The lens is a Tamron 17-50mm f/2.8. Given that, can anyone determine how far away I need to stand at a given focal length?<br>

Thanks!<br>

Bonus question: How would you light this event? Would you do a two light set up with umbrellas, or would you do an on-camera speed light to mimic a paparazzi shoot? </p>

<p> </p>

<p>Mmmm.... Math. Lets say you're shooting at 50mm on the APS Sensor Rebel. So, given that, we have an angle of view which is the equivalent of 50mmx1.6=80mm on 35mm, which is 22.875 degrees.<br>

Okay, so now we have to consider the crop factor from APS (15mmx22.5mm for APS-Canon) to 4x6. 4x6 is a 1:1.5 aspect ration, APS-C is also 1:1.5. Perfect. We can ignore this part...<br>

So we have a 2x3 square in the middle to work with.... time for me to do drawings. Okay, so our angle of view is halved again, because of the crop by the frames to half the size, so we're down to 11.43725 degrees.<br>

I used a person and a 50mm lens on a 35mm camera for reference, resulting in approximately 1.5 feet for a image of a face, full crop. That would be 39.6 degrees, by the by.<br>

So now we can solve. 39.6 degrees/11.43725 degrees x 1.5ft = 5.19 ft for 2x3 inch centered faces on 4x6 prints at 50mm with your lens. You can easily change focal lengths by doubling the degrees for each time you decrease the focal length by half.<br>

For a full frame body on the other hand, we have an approximately 8 foot distance with that same lens, and thus 39.6/11.43725x8=27.69 ft. I'd suggest halving the focal length to 25mm in order to get around 14 ft.<br>

Hope that was somewhat helpful.</p>

<p>Practice and then put low tack painters tape on the LCD on the camera to make sure your shots are sized right when you chimp.</p>

<p>:D I don't understand a word of Andrew's explanation, I have a poor mind considering math... If I were in your position I'll use the longest focal length to keep the postures seen from the best proportion and stand as far as possible, then closing in to get the best framing, but it'll depend on how wide is your space. I'm not really familiar with rebel's inner settings, but perhaps there are options where you can turn on the lines to guide your composition, keep the dimension of the frame in your mind while you are composing. If you have found the sweet spot, keep that position as constant as possible.</p>

<p>I've seen photos of children with on camera speedlights, and I have to say they are quite horrible. Depending on the venue (outdoor/indoor?). Setting up a lightstand (or two) with no one to guard it in a place with a lot of children might not be the best of idea. If you can, swivel - tilt your on camera flash to bounce from any surface around you (if there is any) keep your iso at the highest usable level, aperture somewhere near the widest (depends on single or group) and usable shutter speed (for children). Using the bounce card might result in boring pictures and useless if there's no usable ceiling.</p>

<p>Other options that I usually use when I don't have the options both to bounce and to use lightstands setups, is handholding my flash high to the side with one hand, triggering it with radio or optical and shoot with my other hand. Prepare a small bag to your side though, to slip in the flash in case you need both of your hands.</p>

<p>Oh, and do some test shots... good luck.</p>

I have a hard time figuring out this frame. Will the frames be displayed horizontally so the 6 x 4 (width x height) frame will show a 3 x 2 (width by height) horizontal section?

 

Or, Will the frames be displayed horizontally so the 6 x 4 (width x height) frame will show a 2 x 3 (width by height) vertical section?

 

Or, will the frames be displayed vertically so the 6 x 4 (height x width) frame will show a 3 x 2 (height by width) vertical section? (You would have to hold the camera vertically for this.)

 

It seems like the vertical or portrait mode would be best. Framing out the LCD panel with painters tape seems like a very good idea. If your viewfinder has an optional grid you could use that also.

<p>It is not about the Mathematics of the Shooting Distance and the Focal Length – neither matter for your concern.<br /> <strong><em>It is all about the consideration of the framing of the girl in the viewfinder and what Type of Shot it is to be.</em></strong><br /> <strong><em> </em></strong><br /> I assume the Picture Frame will sit Vertical.</p>

<p>The border of the Picture Frame encroaches on the sides by 1 inch and at the top and the bottom by 1½ inches – or does it? – (some inserts have more at the bottom than the top).<br /> But let’s assume an even border – 1” at the sides and 1½” at the top and bottom.<br /> You need choose what type of shot? Full Length, Half Shot Tight Bust Shot . . .<br /> A Full length Shot (IMO) would look silly in such a small print with such a large border – so maybe an Half Shot would be best?</p>

<p>If an Half Shot – then you will need to frame the shot with a lot of air on top.<br /> A (typical) 7 year old girl is just under 4ft tall – that means when the Half Shot is placed in the frame and the border you will want about 24 inches of the girl showing and that is with her head just clearing of the top of the border when the print is inserted . . .<br /> So that means you shoot Vertical Format with the bottom of your frame –<em><strong> cutting each Child just ABOVE their KNEES</strong></em> as you look through the Viewfinder and ensure each girl is <em><strong>in the centre of the frame.</strong></em><br /> That will fill the 3 x 2 inch area with an image from about their hips/belly button to their head and with their head clear of the top of the insert.<br /> If you have an unusually tall Child – then frame her tighter – suggest framing such that the bottom of the frame in the Viewfinder cuts her at the Hips.<br /> It won’t matter what Focal Length and Shooting Distance – for the “average, just shorter than 4ft, 7 year old girl" - it is all about <strong>The Shot</strong> and how you <strong>Frame it</strong> (in the viewfinder).<br /> However, working with the Lens at 50mm will give a pleasing perspective and nice workable Shooting Distance – and it is easy to use 50mm for all the shots if you can.<br /> Do a few test shots and prove this for yourself.<br /> ***<br /> Bonus points Answer -<br />On Camera Flash – White Bounce Card – Paparazzi Style.<br>

If you have a Flash Bracket, then all the better as you will be shooting Vertical Format – but If not a White Bounce Card will (have to) suffice.<br>

<br /> Reason – you need to be mobile and quick – nail two shots of each girl if you can – choice is always nice to have.<br /> ***<br /> Extra Bonus points – measure the frames and the inserts, <strong><em>yourself</em></strong>.</p>

<p>WW</p>

<p>Is there absolutely no chance of having a few minutes on a laptop before heading over to CVS for printing? Almost any editor - even the free ones - will let you take your full frame, re-sample it down to 2 x 3 inches at 300dpi, and then increase the paper/canvas size back up to 4 x 6 (leaving a nice margin). This lets you shoot <em>what you see in the viewfinder</em> and after about 30 seconds per image before you go to print, make it fit perfectly to the display frame.</p>

<p>^ I like Matt's lateral thinking option, as the best "how to the job" answer.<br>

Well worth making time and the laptop available - "KIS"</p>

<p>Addendum - scale the image to just a tad <strong>larger</strong> than 3 x 2 so that the border of the insert has a nice rebate to the edge of the image.</p>

<p>Seems easy to me!<br /> Your camera has a large LCD view screen on its hind side. Measure the height and width of this view screen. Now construct a mask overlay. You could use masking tape or a rectangular cutout made from construction paper. You could use a transparent overlay and rule the dimensions. We call such as ruled overlay a reticule. Rule the lines boldly, maybe add some crosshatches to clearly set the limits of the desired rectangle.</p>

<p>Your view screen depicts a 1:1.5 rectangle i.e. 4x6 size. You mealy mark a revised rectangle measuring 50% of the height and 50% of the length. A transparent reticule allow you to see what is outside the boundaries, now you can step back or change the zoom with to suit your taste.</p>

<p>Very rough but simple answer:<br>

If a certain subject fills the frame at a certain focal length (and therefore also fills a 4x6 print), keeping everything the same BUT using a lens of half the focal length will fill up a 2x3. So if you had a zoom lens with a 2x range (which every zoom has) you could fill the frame at (say) 70 mm and then zoom to 35 mm and take the picture. </p>

<blockquote>

<p>"Seems easy to me! Your camera has a large LCD view screen on its hind side. . . " </p>

</blockquote>

<p>AM -<br>

I might be missing a step, but:</p>

<p>I don’t think all Rebel Models have live view.<br>

If the OP’s camera does have live view –<strong> then is this the mode (Live View) which is being suggested to use?</strong><br>

Otherwise, grid lines or a cut-out on the LCD on the rear of the camera (or the swing out LCD) <strong>will only render the framing, after the shot is made – is this what is being suggested?</strong></p>

<p>WW</p>

<p>I like the idea of masking the LCD. But to William's point, I would not use live view. But you could do a couple of test shots to see where you need to be for the girl to fit within the masked area. Have an x on the floor where the girl stands and -- after your test shot (before things begin) -- have an x on the floor for the photographer. Once you've got that worked out, don't change anything. As for lighting, speedlight on the camera is fine. Use a diffuser or bounce card if you like, but these are really snapshots for little girls so don't know yourself out. How many pictures do you need to do? The Epson PictureMate or the small Canon dye sub 4x6 printer would be perfect for this and save you the trouble of running back and forth, maybe standing in line or finding out the machine at the store is being serviced at the particular moment of the day. You probably arent' doing enough shots that the printer could pay for itself but if you have one or could borrow one it would be useful.</p>

That 2x3 inch opening bothers me. In essence you would have a larger viewable image if you contact printed 120 film shots. Since the red carpet is a big deal, they would want that showing. That would call for full length shots in that 2 x 3 inch opening.

 

People's expectations may exceed what is possible. "We want some nice head and shoulders shots of the girls but be sure to include their party dresses and the red carpet,"

<p>I haven’t seen a digital camera minus the LCD screen in years. I think all of the Canon Rebels allow two methods to compose, a viewfinder and the LCD screen. If perchance the Howie does not have a camera with such viewing ability, I would suggest he scrounge one up.</p>

<p>As for live view, us gray hairs are known to have spent some time under the black focusing cloth to compose on the ground glass of those now antique cameras, we managed! Often we ruled the ground glass for different image sizes, sheet film, roll film, and we even masked the film holders, making two or four separate exposures on a single sheet of film to economize.</p>

<p>2 x 3 is such a small opening, which means that their photos will have to be tiny. Have you thought about just getting bigger frames for the girls to decorate that have an actual 4x6 opening? Inexpensive and readily available at any big craft supply store.</p>

<p>“Live View” is the Canon term for the functionality allowing Composition and Focussing, on the LCD Screen.<br /> Certainly, the Rebel XTi (400D) doesn’t have Live View and the XSi (450D) does. We own both of these cameras. I expect it is at that point in the Rebel Development Live View became available, but I am not sure.</p>

<p>***</p>

<p>Buying or borrowing a new or another camera to have the Live View function is not necessary.<br /> Also, it is my opinion that using Live View, is not a good idea for this job, anyway.</p>

<p>***</p>

<p>A “Red Carpet Shoot” conjures in my mind an “Event”, with movement.<br /> The OP confirms the elements of The Shoot here:<br /> <em>“</em>My sister-in-law has asked if I would be so kind as<em> to take pictures of the girls <strong>as they are entering the party</strong> on the red carpet”</em></p>

<p>i.e. these 7 year olds will, be walking (entering the room/ venue) down a Red Carpet, much like the Processional at a Wedding.<br /> The “Event” – the act of entering on a Red Carpet - is the element which is to be captured – it is not a Static Portrait Shoot, like days of old, where Ground Glass Focussing Screens, Camera Hoods and Neck Braces for the Subjects could be used.<br /> Hence previous comments regarding mobility (of Flash Gear) and speed of movement (of the Photographer).</p>

<p>***</p>

<p>However, I might have misinterpreted the elements of what the Shoot is all about and / or the OP might be able to manipulate what is to be captured and how it is to be done:<br /> The Girls might be able to be corralled and their Photographs taken in an orderly, controlled and prescribed fashion, as per a Camera Booth set up an the event.<br /> In which case, a “Red Carpet Shoot” is not the best description; and the images will be different to those which the OP’s Sister-in-law, originally requested.</p>

<p>***</p>

<p>Having such a small (3" x 2") picture concerns me also, which is why I mentioned that a Full Length shot would look silly (being so small a Print) - and why I based my original comments on making an Half Shot for the Frame and Insert.</p>

<p>WW</p>

<p>Open the image in Photoshop and adjust Image -> Canvas Size to extend a white border around the actual image. That will push the actual image into the center of the bordered frame.</p>

<p>Better framing through software! :-)</p>

BTW, you can't use math for this situation. The seven year olds may vary in height from 4' 2" to 5' 2". Set your lens focal length according to the distance to a 4' 2" child and you will end up cropping off the top of the 5' 2" child's head. You are going to have to do the framing in camera, either with a masked off LCD, grid lines in the viewfinder or empirically.

<p>I believe there are places that will make 2x3 prints. If not some home printers will make 2x3 prints. My HP does. So just shoot normally and make 2x3 prints that you can tape into the holder. If you can't find 2x3 prints look for wallet sized prints. They should be 2x3 or close to it.</p>

<p>Wow, a lot of great responses everyone. I don't know where to start responding!<br>

The camera is the XTi, no Live View. However, I got a lot of great ideas here and will arrive early enough to do test shots.<br>

Worst case scenario, I get fired by my sister-in-law. Oh well.<br>

Thanks!<br>

Howie</p>

<p>Big thanks to everyone. The shoot went great. I set up on the driveway. My sister-in-law had a cheesy plastic backdrop that looked like a red curtain. We taped it to the garage door. She had a narrow red carpet we rolled right up to the garage door. Each girl in turn stood on the carpet about five feet in front of the back drop. I had a single speedlight on a high stand shooting through an umbrella at camera right. I positioned the camera about 12 feet in front of the subject and zoomed out to 50mm. I framed the subject in the center and shot away, taking care to leave a lot of space around the sides.<br>

The results were great, or should I say, good enough for a 7-year-old's birthday party.<br>

Thanks everyone for your help!<br>

Howie</p>

 

<p>Good one!</p>